In dense wavelength division multiplexing (DWDM) optical networks, managing the physical media by tracing signal paths is considered a very challenging task. Since the optical signals are analog signals, confirming connectivity and continuity is difficult without converting them to electrical signals. The problem is exacerbated when complex network elements such as all-optical switches, dynamically re-configurable optical add-drop multiplexers (OADM) etc. are added to the optical network. Optical networks currently do not have a complete data communication infrastructure that will support in-fibre signalling between all of the network elements.
Current techniques for detecting the presence and absence of discrete optical channels in an optical network use analog signals that propagated throughout the network, thereby making it susceptible to signal degradation as well as making it difficult to terminate and regenerate the signals at each node. Since most of the techniques rely on a sub-carrier in-channel dither, they impose an optical penalty which affects the overall link budget. In situations where wavebands are routed at an OADM site, current technologies rely on correlation of individual analog signals to determine the routing. Most importantly, these technologies rely on the carrier optical signal being present to determine the routing of the fibres. The nature of these technologies prevent them from being used as a network management communications channel.
Therefore, it is desirable to provide a network management communication infrastructure that will support in-fiber signaling between all of the network components residing in the optical network.